Short-term Borrowings and Long-term FHLB Advances - Information Concerning Short-term Borrowings (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Long-term Federal Home Loan Bank Advances [Abstract]
Balance at period-end	$ 72,161	$ 493,219
Maximum amount outstanding at any month end	174,431	493,219
Average balance outstanding during the period	$ 83,733	$ 129,545
Weighted-average interest rate, as of the period-end (as a percent)	0.26%	1.82%
Weighted-average interest rate, paid during the period (as a percent)	0.84%	2.07%